The aim of this study was to investigate the proportion of 3 Neil's classifications of lateral throat forms and the difference in the length of the lateral throat form between the dentures and the patient's actual anatomy. The classification of lateral throat form was determined by the patient's functional movements, and an implant depth gauge was used to measure the length of the lateral throat form in the patient's mouth and compare it to that of the dentures. One hundred mandibular edentulous patients were measured. The proportion of Neil's Class I lateral throat form was 70%, the proportion of Class II was 25%, and the proportion of Class III was 5%. The mean difference between the actual lateral throat forms and the dentures was 6.7 +/- 2.9 mm at the anterior point of measurement (from the anterior part of the retromolar pad to the mouth floor) and 10.0 +/- 3.7 mm at the posterior point (from the middle of the retromolar pad to the mouth floor). The difference in length between the ridge height of the mouth and the denture was statistically significant (P < .001).

The objective of this study was to assess whether a periodontal probe measurement could be used to obtain a predictable reproduction of the buccal shelf areas in mandibular dentures. One hundred patients were measured for the anterior, middle, and posterior width of the buccal shelf with a periodontal probe. This measurement was then compared with that of the corresponding portion of the existing denture. At each portion, there were statistically significant differences in the width of the buccal shelf and that of the corresponding portion of the existing denture from dental clinics of general dentists. The periodontal probe could be used to measure the width of the buccal shelf to obtain a predictable reproduction of the buccal shelf areas in mandibular dentures.

Statement of problem. Fabricating dentures for the patient with severe mandibular atrophy can be a challenge for both the dentist and patient. Subperiosteal implants with a mandibular overdenture may be a solution for the atrophic mandible.Purpose. The purpose of this retrospective study was to review the survival of mandibular subperiosteal implants placed at the University of Missouri Kansas City (UMKC) School of Dentistry Graduate Prosthodontics program between 1982 and 2000.Material and methods. Forty subperiosteal implants were placed in atrophic mandibles of 40 patients (33 women, 7 men) between 1982 and 2000. The age range of the patients was 47 to 80 years of age at time of placement (mean = 62 years). Each patient was reviewed clinically by an author (DJM). Manual depression and lifting of the framework were used to evaluate the stability of the implant. Additionally, the implants were observed for any movement. Each patient was questioned for pain or discomfort. Each patient was examined for observable inflammation and intraoral exposure of the framework and questioned as to whether the implant had satisfied the patient and met the patient's expectations.Results. Thirty-nine of the 40 original patients were recalled in 2000. One patient had died. Fourteen patients had implants for over 10 years, 12 patients had implants between 5 and 10 years, and 12 patients had implants for less than 5 years (mean time of implant service = 8 years). Thirty-eight patients had the implant in place with no sign of inflammation or mobility, I patient with diabetes had inflammation around one of the struts. All patients were wearing their prostheses, and there was no sign of exposed implant framework for any patient. All patients reported a high level of satisfaction with the implant.Conclusions. Within the limitations of this study, the mandibular implants placed at UMKC were still functioning, and all patients denied any discomfort or pain from the prostheses. Patients reported they were comfortable and able to function with the implant-supported prosthesis.

Journal of ProsthodonticsVolume 11, Issue 4 p. 328-328 A new Maxillomandibular relationship Recorder (a central bearing device) Leslie Young Jr. DDS, MS, Leslie Young Jr. DDS, MS Professor Emeritus, University of Missouri-Kansas CitySearch for more papers by this authorDorsey J. Moore DDS, Dorsey J. Moore DDS Professor Emeritus, University of Missouri-Kansas CitySearch for more papers by this author Leslie Young Jr. DDS, MS, Leslie Young Jr. DDS, MS Professor Emeritus, University of Missouri-Kansas CitySearch for more papers by this authorDorsey J. Moore DDS, Dorsey J. Moore DDS Professor Emeritus, University of Missouri-Kansas CitySearch for more papers by this author First published: 09 August 2004 https://doi.org/10.1111/j.1532-849X.2002.328_2.xRead the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume11, Issue4December 2002Pages 328-328 RelatedInformation

PURPOSE:The study investigated the effects of palatal depth and a resin anchoring system on the adaptation of denture base resin to the master cast after compression molding and heat polymerization.MATERIALS AND METHODS:Forty-eight virtually identical polymethyl methacrylate dentures were fabricated on master casts with either a deep or shallow palatal vault. One half of the master casts of each palate type were altered by the addition of anchoring holes along the posterior land area, as well as perpendicularly in the midsaggital area. Anchoring holes were made with a #8 round bur to a depth of 5 mm. Twenty-four hours after polymerization, the bases on their casts were sectioned at the posterior border and evaluated for degree of adaptation using a traveling microscope. Maladaptation at the interface of the denture base and master cast was measured at predetermined mediolateral locations. A split-plot analysis of variance (alpha = 0.05) was performed followed by a post-hoc Dunn Multiple Comparison Test.RESULTS:In general, depth of the palatal vault did not significantly influence denture palatal discrepancy (p =.0780), but the use of the anchoring system significantly reduced mean gap distances (p =.000). At lateral and midpalate locations, gap distances between the denture bases and their casts were reduced from approximately 0.3 mm to approximately 0.1 mm when the anchoring system was used.CONCLUSIONS:Mean gap distances for steep palate dentures were significantly less than shallow palate dentures at vestibule and lateral palate locations, and anchoring holes placed in an edentulous master cast along the posterior land area and at the midline significantly improved the adaptation of denture bases.

PURPOSE:This investigation introduces percent adherent area and 10-minute and 8-hour peel-strength values as an in vivo evaluation of three popular maxillofacial prosthetic adhesives when used with three extraoral prosthetic polymers.MATERIALS AND METHODS:Specimens of Silastic MDX 4-4210, Silastic Medical Adhesive A (Dow Corning Corporation, Midland, MI), and Silicone A-2186 (Factor II, Inc, Lakeside, AZ) were adhered to 25 subjects' arms using Secure Medical Adhesive (Factor II, Inc), Pros-Aide Adhesive (ADM Tronics Inc, Northvale, NJ), and Hollister Colostomy Adhesive (Hollister Inc, Libertyville, IL). After 10 minutes, the peel strength required to remove the specimens was measured. Additional specimens were then adhered to the subjects and worn for 8 hours. The nonadherent areas of the specimens were then marked, the peel strength was measured again, and then the percent adherent area was calculated.RESULTS:Hollister Colostomy Adhesive showed greater 10-minute peel-strength values when used with Silastic Medical Adhesive A. The peel-strength values of the Hollister Colostomy Adhesive when used with Silastic MDX 4-4210 increased with time. The greatest percent adherent area was obtained with Silastic MDX 4-4210 using Pros-Aide Adhesive, and the lowest was obtained with Pros-Aide Adhesive using Silicone A-2186 and Silastic Medical Adhesive A.CONCLUSIONS:There was no clearly superior adhesive/prosthetic material combination based on the tests used in this study; however, individual skin variations between patients affect the adhesive properties.

Four experiments in this study assess shade differences in acrylic resin denture and natural teeth. The first two examine the perceptual errors made by experienced dentists in their use of a manufacturer-provided shade guide for acrylic resin denture teeth. In the first of four experiments, dentists examine whether the numbering of a selected shade guide corresponds to the arrangement of the tabs from light to dark. In the second experiment, a visual discrimination task determines whether dentists can distinguish shade guide tabs from one another. The results from these two experiments revealed that the numbered progression of the shade tabs does not correspond to a light-to-dark order, that dentists have difficulty discriminating between several shade tabs, and that the shade tabs can be rearranged on an empirical basis. The third experiment demonstrated how the shade of natural teeth varies by age, gender, and complexion. The Biotone shade guide, rearranged in the manner suggested by the second experiment, was used to make these assessments. The fourth experiment examined whether the shades used for complete dentures were similar to shades found in natural teeth. The results from the last two experiments showed that shade selection can be facilitated by use of a rearranged set of shade guide tabs. The results also reveal that natural teeth significantly and clinically darken with age; however, selections made for denture teeth tend to be relatively constant in color, despite the age of the patient. Differences for gender and complexion do not appear to be clinically significant.

There is no precise scientific method for determining the correct edentulous occlusal vertical dimension. This study established the proportion between the ear-eye to chin-nose distance for determining reasonable occlusal vertical dimension. Two hundred white and 400 Asian men and women participated in this study. The ear-eye and chin-nose distances were measured with a modified craniometer. The results revealed that left ear-eye distance can be used to predict chin-nose distance with reasonable accuracy. However, the algorithm for making this prediction is not the same for combinations of sex and ethnic origin.

A survey was conducted to examine the current status of maxillofacial prosthetics programs. Their relationship to private practice, compared curriculums, patients, and other recent changes of merit were evaluated, and the results of the survey are presented.

Purpose The purpose of this study was to test the Hanau Modular Articulator system with programmed fossae to determine its interchangeability.Materials and Methods Eight Hanau Modular Articulators were tested using the same measuring system as previously developed in a similar investigation on a different instrument.Results It was determined that the Hanau Modular System with programmed fossae did possess accuracy when a measuring device was transferred between the eight articulators tested.Conclusions Laboratory procedures for multiple restorations can be accomplished with accuracy when master casts and mountings are transferred between Hanau Modular Articulators.

The in vitro physical properties of two types of polydimethyl siloxane, MDX 4-4210 and a new material A-2186, were compared. The properties that were investigated in this study were tensile strength, elongation, tear strength, and surface hardness. The properties tested were selected because of their clinical significance for fabricating a facial prosthesis. According to the results obtained in this investigation, the new material, A-2186, had greater tear resistance, tensile strength, and a larger percentage of elongation. A-2186 material, also proved to be softer at the surface than the MDX 4-4210. This combination of physical properties makes this material, A-2186, a better choice than the traditional MDX 4-4210 for the fabrication of facial prostheses.

This study applied the three-dimensional measurement technique of stereophotogrammetry to measure abutment tooth movement under occlusal loading as a function of intracoronal attachment and clasp design. Six distal-extension removable partial denture designs were studied: (1) RPI-mesial occlusal rest, proximal plate, buccal I-bar; (2) cast circumferential clasp; (3) P.D. locking semiprecision attachment; (4) Thompson dowel nonlocking semiprecision attachment; (5) McCollum precision attachment; and (6) Stern G/L precision attachment. The movement in microns was determined by computer analysis. The Thompson dowel semiprecision attachment generated the most abutment movement in a gingival direction. The clasp-retained designs generally had less total movement than the attachment designs. Clasps and attachments for the abutment teeth adjacent to the distal-extension bases generally moved more than the abutment teeth.

This investigation photoelastically compared the load-transfer characteristics of various bilateral distal-extension removable partial denture designs embodying intracoronal attachments and clasp assemblies. Six distal-extension designs that included the RPI clasp assembly, cast circumferential clasp, P.D. locking semiprecision, Thompson dowel nonlocking semiprecision, and McCollum and Stern G/L precision attachments were tested. Each prosthesis was subjected to various simulated occlusal loads. Evaluation of the load-transfer characteristics of the various designs was based on comparison of the recorded isochromatic fringe distributions. The RPI clasp assembly generated the most uniform stresses. In general, the four intracoronal retainer frameworks produced higher stresses than did the two clasp frameworks. The highest stresses were developed by the Stern G/L precision attachment.

S urgical removal of tumors in or adjacent to the maxillae is the most common cause of acquired palatal defects.’ As surgical techniques advance, prosthodontic needs advance, and more patients become candidates for maxillofacial reconstruction. In the treatment of soft palate defects, many concepts have been presented since the flap velum was first reported in 177g2 The flap velum attempted only to cover the tissue defect with a mechanical seal in the hope of improving speech and function. At the present time, conventional or rigid obturation similarly involves extending methyl methacrylate resin to the level of greatest muscular activity exhibited by the residual palatopharyngeal complex.3 This prevents leakage of material into the nasal cavity during swallowing and modifies hypernasality during speech. However, as early as 1871 the idea of replacing missing tissue as well as stimulating its physiologic function was presented. The use of unvulcanized rubber had been proposed in 1823 for a soft palate prosthesis.’ Thus we hypothesize that a flexible silicone obturator might better serve the needs of patients with surgically acquired defects of the soft palate. This hypothesis is based on the dynamic changes of the normal soft palate. During speech, the normal soft palate and pharyngeal muscle complex will always be in dynamic equilibrium among the three positions shown4 (Fig. 1). The nasal and oral cavities will be momentarily but perfectly occluded at the positions shown in Fig. l., B, and Fig. 1, C, respectively. These diagrams also represent the position of the soft palate during articulation of consonants and vowels (Fig. 1, B) and nasalized phonemes /m/, /n/, and /ng/ (Fig. 1, C). Would a flexible, silicone obturator be more likely to approximate these positions than the static acrylic resin obturator? Would the patient sound better or worse with the new material? The answers were sought through instrumental and perceptual tests of one rigid and two flexible obturators.

A new silicone material, Silastic MDX 4-4210, was tested by tissue culture and tissue implantation to compare host reaction with known toxic and nontoxic materials. It was not found to be toxic to a monolayer of HEL cells, and it evoked a minimal foreign body reaction when implanted in albino rats. Further clinical studies are indicated to evaluate host reaction of this silicone in long-term contact with human mucous membrane and skin tissue.

Major head and neck trauma affects the midface and intraoral structures in most accident victims. The prosthodontist can provide a much-needed treatment service during the rehabilitation of these persons. Secondary management is a complicated and protracted experience. An interdisciplinary approach with consultations, careful planning, and integrated surgical/prosthodontic management of all phases of treatment can provide the patient with a most satisfactory result.

The methods for initial evaluation of a new prospective maxillofacial prosthetic material, MDX-4-4210, have been described and tensile and compressive test data have been obtained. Evaluation of the data indicates that this is a promising material with significant potential for use in maxillofacial prosthetics. Further studies of the material's biologic implant compatibility, its chemical and environmental stabilities, and its clinical performance are being done.